Understand the concept of flag for new users

Hello every,

I am a very very new user of Graphhopper and I am recently going through the code for a better understanding of the algorithm. However, I am quiet confused about the flag concept used in this algorithm. Is there any document that elaborate more in this concept? Thanks here in advance for any reply.

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This is nothing important for the algorithm. With this technique we retrieve edge properties in a memory efficient way. E.g. instead of two booleans in an Edge object which would require roughly two byte or even 4 as it could introduce memory alignment, we just use two bits and have space for other data in the 4 or 8 bytes.